Freya radar
Encyclopedia
Freya was an early warning radar
deployed by Germany during World War II
, named after the Norse Goddess Freyja. During the war over a thousand stations were built. A naval version operating on a slightly different wavelength was also developed as Seetakt
. Freya was often used in concert with the primary German gun laying radar, Würzburg Riese
("Würzburg Giant"); the Freya finding targets at long distances and then "handing them off" to the shorter-ranged Würzburgs for tracking.
First tests of what would become the "Freya" were conducted in early 1937, with initial delivery of an operational radar to the Kriegsmarine
in 1938. Later in the war Freya operated in the band from 2.5 to 2.3 meters / 120 to 130 MHz, with a pulse width of 3 microseconds, a peak power output of 15 to 20 kW
, and a pulse repetition frequency
of 500 Hz. However it had a maximum range of only 160 kilometres (99.4 mi) and could not accurately determine altitude, making it inferior to the British Chain Home
system in those respects, but it was a fully steerable and semi-mobile system.
One of the first to give the British intelligence about the Freya Radar was a young Danish Flight Lieutenant Thomas Sneum
, who, at great risk to his life, photographed radar installations on the Danish island of Fanø
in 1941. He brought the negatives to England in a dramatic flight which is fictionalized in Ken Follet's novel Hornet Flight
. Sneum's deed is also mentioned in R. V. Jones's
Most Secret War as a 'most gallant exploit'.
s of the Special Duties Flight (later 515 Squadron), a single set retransmitted a portion of the Freya signal amplifying the apparent return. Eight aircraft with Moonshine could mimic a force of 100 bombers. A second countermeasures system, "Mandrel" was a noise jammer which overwhelmed the signals from Freya. Individual aircraft were sent to orbit fixed positions 50 miles (80.5 km) off the enemy coast. By using nine aircraft a 200 miles (321.9 km) gap could be knocked in the German's radar coverage, while further jammers were carried in the bomber stream to deal with the inland Freya network.
Early warning radar
An early warning radar is any radar system used primarily for the long-range detection of its targets, i.e., allowing defences to be alerted as early as possible before the intruder reaches its target, giving the defences the maximum time in which to operate...
deployed by Germany during World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
, named after the Norse Goddess Freyja. During the war over a thousand stations were built. A naval version operating on a slightly different wavelength was also developed as Seetakt
Seetakt radar
The shipborne Seetakt radar was developed in the 1930s and was used by the German Navy during World War II.In Germany during the late 1920s, Hans Hollmann began working in the field of microwaves, which were to later become the basis of almost all radar systems. In 1935 he published Physics and...
. Freya was often used in concert with the primary German gun laying radar, Würzburg Riese
Würzburg radar
The Würzburg radar was the primary ground-based gun laying radar for both the Luftwaffe and the German Army during World War II. Initial development took place before the war, entering service in 1940. Eventually over 4,000 Würzburgs of various models were produced...
("Würzburg Giant"); the Freya finding targets at long distances and then "handing them off" to the shorter-ranged Würzburgs for tracking.
First tests of what would become the "Freya" were conducted in early 1937, with initial delivery of an operational radar to the Kriegsmarine
Kriegsmarine
The Kriegsmarine was the name of the German Navy during the Nazi regime . It superseded the Kaiserliche Marine of World War I and the post-war Reichsmarine. The Kriegsmarine was one of three official branches of the Wehrmacht, the unified armed forces of Nazi Germany.The Kriegsmarine grew rapidly...
in 1938. Later in the war Freya operated in the band from 2.5 to 2.3 meters / 120 to 130 MHz, with a pulse width of 3 microseconds, a peak power output of 15 to 20 kW
Kw
kw or KW may refer to:* Kuwait, ISO 3166-1 country code** .kw, the country code top level domain for Kuwait* Kilowatt* Self-ionization of water Kw* Cornish language's ISO 639 code* Kitchener–Waterloo, Ontario, Canada...
, and a pulse repetition frequency
Pulse repetition frequency
Pulse repetition frequency or Pulse repetition rate is the number of pulses per time unit . It is a measure or specification mostly used within various technical disciplines Pulse repetition frequency (PRF) or Pulse repetition rate (PRR) is the number of pulses per time unit (e.g. Seconds). It...
of 500 Hz. However it had a maximum range of only 160 kilometres (99.4 mi) and could not accurately determine altitude, making it inferior to the British Chain Home
Chain Home
Chain Home was the codename for the ring of coastal Early Warning radar stations built by the British before and during the Second World War. The system otherwise known as AMES Type 1 consisted of radar fixed on top of a radio tower mast, called a 'station' to provide long-range detection of...
system in those respects, but it was a fully steerable and semi-mobile system.
One of the first to give the British intelligence about the Freya Radar was a young Danish Flight Lieutenant Thomas Sneum
Thomas Sneum
Thomas Christian Sneum was a Danish pilot born May 21, 1917 at Fanø, Denmark. Died February 3, 2007 in RoskildeHe collected information about the German Freya radar that was installed at his home island in Denmark....
, who, at great risk to his life, photographed radar installations on the Danish island of Fanø
Fanø
Fanø is a Danish island in the North Sea off the coast of southwestern Denmark, and is the very northernmost of the Danish Wadden Sea Islands...
in 1941. He brought the negatives to England in a dramatic flight which is fictionalized in Ken Follet's novel Hornet Flight
Hornet Flight
Hornet Flight is a World War II based spy thriller written by British author Ken Follett. It was published in 2002 by Macmillan in the UK and Dutton in the US.-Plot introduction:...
. Sneum's deed is also mentioned in R. V. Jones's
Reginald Victor Jones
Reginald Victor Jones, CH CB CBE FRS, was a British physicist and scientific military intelligence expert who played an important role in the defence of Britain in -Education:...
Most Secret War as a 'most gallant exploit'.
Countermeasures
To counter Freya, the British used equipment called "Moonshine". Carried by Boulton Paul DefiantBoulton Paul Defiant
The Boulton Paul Defiant was a British interceptor aircraft that served with the Royal Air Force early in the Second World War. The Defiant was designed and built by Boulton Paul Aircraft as a "turret fighter", without any forward-firing guns. It was a contemporary of the Royal Navy's Blackburn Roc...
s of the Special Duties Flight (later 515 Squadron), a single set retransmitted a portion of the Freya signal amplifying the apparent return. Eight aircraft with Moonshine could mimic a force of 100 bombers. A second countermeasures system, "Mandrel" was a noise jammer which overwhelmed the signals from Freya. Individual aircraft were sent to orbit fixed positions 50 miles (80.5 km) off the enemy coast. By using nine aircraft a 200 miles (321.9 km) gap could be knocked in the German's radar coverage, while further jammers were carried in the bomber stream to deal with the inland Freya network.
See also
- Würzburg radarWürzburg radarThe Würzburg radar was the primary ground-based gun laying radar for both the Luftwaffe and the German Army during World War II. Initial development took place before the war, entering service in 1940. Eventually over 4,000 Würzburgs of various models were produced...
- List of World War II electronic warfare equipment
- Operation TaxableOperation TaxableOperation Taxable was the codename for one of the deception operations used by the Allied forces during World War II in connection with the Normandy landings...
- Operation GlimmerOperation GlimmerOperation Glimmer was the codename for one of the deception operations used by the Allied forces during World War II in connection with the Normandy landings . In conjunction with Operation Taxable, this was conducted by aircraft of the Royal Air Force and small ships of the Royal Navy to trick the...
External links
- Deflating British Radar Myths of World War II A comparison of contemporary British and German radar technologies and their use